Hydraulic jacks have been used for a number of purposes including emergency rescue devices of the type illustrated in U.S. Pat. No. 3,891,187 issued June 24, 1975 on "Portable Rescue Device" and U.S. Pat. No. 2,200,133 issued May 7, 1940 for "Method and Means for Straightening Out Deformed Automobile Bodies and the Like". Other jacks have been used for pushing and pulling services such as the one disclosed in U.S. Pat. No. 2,483,239 issued Sept. 27, 1949 for "Multiple Pressure Fluid Motor Mechanism for Pushing and Pulling" or for stretching or tightening cables such as the one illustrated in U.S. Pat. No. 3,062,502 issued Nov. 6, 1962 for "Tightening Device for Cables, Chains and the Like Elongated Flexible Elements".